The administration of blood or blood components often plays a critical role in the emergency and/or long term treatment of patients. Blood or the individual components of blood (such as platelets, plasma, red blood cells, etc.) may be administered or transfused to patients to treat a variety of conditions. For example, blood may be administered to a patient to replace blood lost as a result of trauma, while individual blood components may be administered as part of a longer term treatment of patients suffering from cancer or certain blood related diseases. The blood or blood components administered to the patient come from blood previously collected from donors.
One of the most common blood collection techniques, and perhaps the most well-known, is the “manual”collection of whole blood from healthy donors. As commonly understood and as used herein, “manual”collection refers to a collection method where whole blood is allowed to drain from the donor and into a collection container without the use of external pumps or similar devices. This is in contrast to the so-called “automated” procedures where blood is withdrawn from a donor and further processed by an instrument that typically includes a processing or separation device and pumps for moving blood or blood components into and out of the device.
Regardless of whether the blood collection technique is manual or automated, withdrawing blood from the donor typically includes inserting a vein access device, such as a needle, into the donor's arm (and, more specifically, the donor's vein) and withdrawing blood from the donor through the needle. The “venipuncture”needle typically has attached to it, one end of a plastic tube that provides a flow path for the blood. The other end of the plastic tube terminates in one or more preattached plastic blood containers or bags for collecting the blood. The needle, tubing and containers make up a blood processing set which is pre-sterilized and disposed of after a single use.
In the manual technique, the collection container and plastic tubing may also include a volume of a liquid anticoagulant, while in the automated technique, a separate container of anticoagulant may be provided from which the anticoagulant is metered into the flow path and mixed with the incoming whole blood. In any event, anticoagulant is required because of the tendency of blood to clot and adhere to the walls of the plastic surfaces which it contacts.
An important consideration in any blood collection technique or system is ensuring that the system or set does not become contaminated by airborne bacteria or other foreign substances that may compromise the sterility of the system. Thus, the sterility of the above-described disposable blood processing set or system is maintained by minimizing exposure of the flow paths and interiors of the blood containers to the outside environment. Such systems are commonly referred to as “closed” systems.
After collection but prior to transfusion to a patient, the blood is typically tested for determining blood type and the presence of pathogens such as virus, bacteria and/or other foreign substances in the donor's blood. Typically, testing of the collected blood requires obtaining a sample of the blood from the blood donor at or near the time of collection.
One well-known technique of obtaining a blood sample is to simply withdraw or collect the blood remaining in the flow path of the disposable set after donation. This involves removing the needle from the donor, inserting the needle into a vacuum sealed sampling tube or tube and allowing the blood from the flow path to drain into the tube. However, because there is a limited supply of blood remaining in the flow path, there may not be enough blood to provide enough of a sample to perform all of the required or desired testing. Accordingly, if a larger volume or numerous samples of blood are required, the technician obtaining the sample may continue draining the blood from the tubing, eventually withdrawing the collected anticoagulated blood from the collection container. Withdrawing blood from the collection container, however, may be less desirable in that it may expose the collected blood in the collection container to the outside environment. Withdrawing blood from the collection container for sampling also reduces the volume of available blood for later processing and transfusion.
An alternative to collecting anticoagulated blood from the collection container is to clamp off the flow path near the collection container and divert the blood being withdrawn from the donor to a collection (sampling) tube or tube of the type described above. This procedure typically employs a particular type of disposable tubing set having a preattached sampling site on the main flow path. Blood at or near the sampling site may be obtained by piercing the sampling site with a separately provided needle or other piercing device, and attaching a sampling tube thereto. To minimize the risk that the incoming blood (which is intended for later processing and transfusion) will be exposed to the outside environment, the sample is typically collected after completion of the blood donation.
Still another example of a blood sampling system is described in U.S. Pat. No. 5,167,656, which is assigned to the assignee of the present application. That patent describes a disposable tubing set wherein the flow path includes an enlarged sample collection portion. Blood for sampling is collected in the enlarged portion by clamping off the flow path near the collection container and allowing the enlarged tubing portion to fill with blood. Once the desired volume of blood for sampling is collected in the enlarged tubing portion, the needle is removed from the donor and the blood is transferred to a tube by piercing the cap of the tube with the needle and allowing the blood to drain into the sampling tube.
While these known techniques have generally worked satisfactorily, efforts continue to provide further improvements in the area of blood sampling. For example, as set forth above, the sample is typically obtained after the blood product (intended for further processing and transfusion) has been collected so as to preserve the sterility of the closed system. However, if the donation procedure must be terminated before completion, there may not be an opportunity to obtain a sample directly from the donor. Thus, it would be desirable to provide a sampling system in which blood samples can be obtained either before or after donation, but without the risk of compromising the sterility of the system and/or the collected blood product.
In addition, as discussed above, the use of vacuum-filled tubes or tubes is common in blood sampling processes. When such vacuum-filled tubes are used, there is the possibility that the suction may cause the tubing of the blood processing set to collapse and restrict blood flow. Of even greater concern, particularly in small-veined donors, is the possibility that the suction may cause the donor's vein to collapse. Thus, it would also be desirable to provide a sampling system where the risk of donor vein or tubing collapse is minimized.
It would also be desirable to provide a sampling system which is integrated with the blood collection set and requires few separate or external components.
Finally, where the sampling system includes a holder (with a piercing member) for receiving a sampling tube, it would also be desirable to provide a holder that is compact in size, easily sterilized and reduces the risk that the user will inadvertently come into contact with the sharpened tip of the piercing member within the holder.